# Actual dimension of Omega in Graph Slam

I have a doubt about GraphSlam Algorithm introduce in this paper. I add a picture to express my doubts (from page 411, 9th in paper):

As per my knowledge $\Omega$ is the information matrix. So in this algorithm as per 2nd line it is mentioned that $\Omega = 0$. How can I set one zero to a matrix? It is a two dimensional array. So I need an array of values.

2nd doubt: As per line no 3 a $3x3$ matrix add to $\Omega$. How could it be possible because if we turn the page we can see a in line 7 a 6*6 matrix add to $\Omega$. What is the actual meaning of line number 3.

3rd doubt: What is the meaning of $x_0$? Is it a column vector of pose? meaning it represent $x,\ y,\ \theta$?

I want clarify my doubt using a picture.

What is the meaning of adding $\Omega$ at $x_0$?

Please help me to find the solution of these questions.

• Ellena, in the future can you include the page numbers from the book that you are referring to? – koverman47 Jul 12 '18 at 15:49
• Also, checkout Latex tutorials and the Tex Stack Exchange. – koverman47 Jul 12 '18 at 16:20
• I mention the paper here. In that paper pdf page number 9 and actual paper page 411. – Encipher Jul 12 '18 at 18:47
• Ah I see. I edited with page 347 (that's the page from the author's book). Would you change 347 to 411? – koverman47 Jul 12 '18 at 18:51
• Yes. It is very nice of you. I am eagerly waiting for my answer. Page number is not a big deal. But I really cannot understand how could I add a 3*3 matrix with a 6*6 matrix? – Encipher Jul 12 '18 at 18:56